Surface Immobilization of Quaternary Ammonium Compounds for the Enhancement of Antibiotic Efficacy

Author: Shikha Tripathi

Tripathi, Shikha, 2024 Surface Immobilization of Quaternary Ammonium Compounds for the Enhancement of Antibiotic Efficacy , Flinders University, College of Medicine and Public Health

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Presently, bacterial contamination on medical devices has become a major challenge in hospital industry. These medical devices include implants, catheters, and many more. In this research, the issue of bacterial contamination on these implants has been addressed. Previously, various measures have been taken to overcome this issue. One of these measures, is prophylactic antibiotic treatment prior to implant surgery but this could not eliminate this risk up to a desired level. Hence, this issue needs to be resolved because it represents a severe threat to patient health because infections at implant surfaces in human body can also cause death. As per published data from our nanoengineering group, the effect of antibiotics can be influenced by surface chemistry of biomaterials. In the present project, we immobilized glycidyltrimethylammonium chloride (GTAC), a quaternary ammonium compound to a substrate pre-coated with plasma-polymerized allylamine. The aim of this was to enhance the substrate with a strong positive charged compound to investigate our hypothesis. We hypothesized that immobilized GTAC would enhance the substrate surface with an intrinsic antibacterial effect. We also hypothesized that the strong positive charge of the substrate could improve the activity of antibiotics against Staphylococcus aureus in the early stages of cell attachment. To test these hypotheses, we used a series of surface characterization techniques (Static Water Contact Angle, XPS, zeta potential) and biological assays (live/dead, zone of inhibition). Further cytocompatibility of these modified surfaces was tested by THP-1 Cytotoxic assay. The GTAC modified surfaces showed antibacterial activity and bacterial viability was found to be 68% for S. aureus ATCC 25923 where bacterial viability decreased significantly when antibiotic activity of GTAC modified surfaces was tested in synergy with antibiotics. But cytotoxic tests results showed that cell viability of THP-1 cells dropped on the sixth day of the incubation with these GTAC modified surfaces.

Keywords: Medical devices, hospital industry, implants, human health, glycidyltrimethylammonium chloride, bacterial viability, antibiotic activity, cytotoxicity.

Subject: Biotechnology thesis

Thesis type: Masters
Completed: 2024
School: College of Medicine and Public Health
Supervisor: Dr Andrew Hayles